First record of stable isotopes (δ13C, δ18O) and element ratios (Mg/Ca, Sr/Ca) of Middle to Late Jurassic belemnites from the Indian Himalayas and their potential for palaeoenvironmental reconstructions

Abstract

Middle to Late Jurassic belemnites from the Spiti and Zanskar valleys in the Indian Himalayas were used for stable isotope (δ13C, δ18O) and element (Mg/Ca, Sr/Ca) analyses. Although the Himalayan orogeny deformed and altered a large portion of the collected fossils, cathodoluminescence and scanning electron microscopy in combination with analyses of iron and manganese contents allowed the identification of belemnites believed to still retain their original chemical composition. Results indicate a long-term temperature decrease from the Middle Callovian–Oxfordian to the Tithonian, which is proposed to have been caused by a concomitant drift of eastern Gondwana into higher palaeolatitudes. Reconstructed absolute temperatures depend on the used equation and assumed δ18O value of seawater, but most likely varied between 17.6 °C to 27.6 °C in the Kimmeridgian and Tithonian with average values between 22 °C to 24 °C. This way, temperatures were similar to slightly warmer than today at comparable latitudes. The reconstruction of absolute temperatures for the Middle Callovian–Oxfordian was hindered by a larger number of poorly preserved belemnites representing this time interval.

Linking the impact of seismicity on palaeogeographic evolution and sedimentary architecture: A case study from Middle Jurassic succession of Spiti Himalaya

“…The dominance of black shale with occasional calc-arenite beds in F.A-II suggests greater depth than the F.A-I, where the planar laminated shale deposited from suspension falls out in a calm and quiet environment. The earlier studies on palaeoredox suggested that the depositional site was dysoxic-anoxic (Fursich et al 2021; Albert et al 2021). The absence of coarse-grained sediment in an anoxic zone infers depositional site below the wave and storm base.…”

“…The Himalayan sedimentary succession deposited along the north-eastern boundary of India in the southern hemisphere of Tethys holds crucial information on Eocambrian to Eocene (Fig. 2a; Bhargava and Singh, 2019; Fursich et al 2021; Albert et al 2021; Sun et al 2021). The Jurassic succession is mainly preserved at the inner part of the higher Himalayas, often representing the scenario during Gondwana’s disintegration.…”

“…1). The depositional sequence represents a transition from limestone to anoxic black shale (Bhargava and Singh, 2019; Fursich et al 2021; Albert et al 2021). Several studies focus on the change in palaeoclimate and ocean chemistry (Bhargava and Singh, 2019; Fursich et al 2021; Singh et al 2021), while the cause of facies transition is yet to be explored.…”

Jurassic bivalves from the Spiti area of the Himalayas, northern India

“…The Spiti area at the northern margin of the Indian craton bordering the Neotethys during the Late Jurassic occupied a southern palaeolatitude between 20-30° according to the Paleolatitude Calculator of van Hinsbergen et al (2015). The occurrence of high latitude southern taxa at relatively low latitudes can be explained by their restriction to outer shelf and slope environments where, due to upwelling, lower water temperatures prevailed (compare Alberti et al 2021;Fürsich et al 2021). In this context, isothermal submergence may explain the way polar faunas were able to cross the tropics (e.g., Crame 1993).…”

Assessing the Suitability of Native Mollusk Shells for Sclerochronochemistry Studies: An Analysis of Eight Persian Gulf Species

“…Because of the key role of ancient shells and shell fossils in the reconstruction of past climate conditions, they have long been a matter of interest to geological Vernal et al 1992;Geary et al 1992;Goodwin et al 2001;Ullmann et al 2017;Killam & Clapham 2018;Scholz et al 2020;Morán et al 2021), archaeological studies (Quitmyer et al 1997;Leng & Lewis 2016). Indeed, one of the main motivations for the study of bivalves (Müller et al 2017;Huyghe et al 2020;Das et al 2021;Kelemen et al 2021;), gastropods (Cespuglio et al 1999;García-Escárzaga et al 2019;Irie & Suzuki 2020), and extinct species such as belemnites Urey et al 1951;Alberti et al 2021) is to gain insight into climatic conditions.…”